The initiation of the dengue NS1 Ag IND study began on March 8th, 2010 with a study population of donations collected by the American Red Cross in Puerto Rico and the study population was expanded to Monroe County blood collections of the Community Blood Centers of Florida, Inc in August 2010. Testing of collections may be further expanded to include other non-ARC sites in Puerto Rico, or to sites in the continental US with documented local dengue virus transmission. Testing may also include retrospective testing of a repository of samples retained from Puerto Rico during the 2009 epidemic season.Testing will be performed from donors who have read information sheets specific to this study (Dengue Research Study Donor Information).